route.h

/*
    This file is part of kiwitun.

    Kiwitun is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    Kiwitun is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with kiwitun.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file route.h
 * @brief Routing module
 * 
 * Handles packet routing. Gets routes from the kernel and stores them locally.
 * Uses only Netlink and Rtnetlink Linux sockets.
 * Provides route lookup for given address:
 * 1. IPv4 gateway for IPv4 destination
 * 2. IPv6 (or IPv4-mapped IPv6) gateway for IPv6 destination
 * Additionally decodes IPv4-mapped IPv6 to standard IPv4.
*/
#ifndef ROUTE_H_
#define ROUTE_H_

#include "common.h"
#include <stdint.h>
#include <netinet/in.h>

/**
 * @brief Get tunnel IPv4 endpoint address for given IPv4 destination address
 * @return Tunnel endpoint address or 0 (INADDR_ANY) if not found
**/
in_addr_t Route_get(in_addr_t address);

/**
 * @brief Get tunnel IPv6 endpoint address for given IPv6 destination address
 * @return Tunnel endpoint address or in6addr_any (all zeros) if not found
**/
struct in6_addr Route_get6(struct in6_addr address);

/**
 * @brief Unmap IPv4-mapped IPv6 address
 * @param address IPv6 address with IPv4 address inside
 * @return Unampped IPv4 address or 0 (INADDR_ANY) if this is not a IPv4-mapped IPv6 address 
**/
in_addr_t Route_unmap(struct in6_addr address);

/**
 * @brief Initialize routing module, get all available routes and start listening for route changes
 * @return 0 on success, -1 on failure 
**/
int Route_init();

/**
 * @brief Print routing table (IPv4 and IPv6) 
**/
void Route_print();

#endif